On a Dillon, especially the 550.
Make sure you have ZERO up/down movement in the shell plate.
Always seat the primer to the bottom of the case's primer pocket.....
Unique is all I load my SASS ammo with, including SG.
There's a very good reason why it's called 'Unique'.
https://www.alliantpowder.com/reloaders/Powder.aspx?powderid=3
Talk to a MD of one of the matches in Canada.
They will provide you with some documentation you will need for the permits.
Each 'state' in Canada has different requirements.
Do they have the lock inside the grip area?
The factory hammer spring is 17lbs.
The factory trigger return spring is 30oz.
Folks refer to them as New Model Vaqueros.